Valve-gear.



H. FORBES.

VALVE GEAR.

AmfLxoA'rloN FILED Arn.s,19os.

Patented Apr.5, 1910.

2 SHEETS-'SHEET 1A.

l. HS-H u VALVE GEAR.

APPL'IUATION FILED APB. 3, 1908.

Patented Apr.5,1910.

2 SHEETS-SHEET 2.

W MM M a@ W TMA-$555 UNITED sTATEs PATENT oEEioE.

HENRY FORBES, OF SOUTI-IAIVIPTON, ENGLAND.

VALVE- GEAR.

To all whom 'it may concern:

Be it known that I, HENRY FORBES, a subject of the King of Great Britain and Ireland, residing at Southampton, Hampshire, England, have invented new and useful Improvements in and Relating to the Valve- Gear of Direct-Acting Pumping-Engines and the Like, of which the following is a specification.

This invention relates to the valve gear of direct acting pumping engines and the like and has for its object the arrangement vwith my improved valve gear.

and construction of valve mechanism whereby the valve of the operative cylinder can be operated directly by the main piston rod without any intervention of an auxiliary cylinder and in such a way as to get a wide adjustment of point of cut-off and at the same time a rapid cut-oft action.

I am aware that attempts have been made to eifect the operation of the main valve direct from the main pist-on by various means but the deficiencies in action and objectionable mechanical features which have beenv obtained in known apparatus are entirely obviated by my invention.

In order that the invention may be the better understood I will now proceed to describe the same in relation to the accompanying drawing, reference being had to the letters and figures marked thereon.A

Figure l is a part sectional side view of the mechanism of a pumping engine fitted Fig. Q, is a front view of same. Fig. 3 is a detail view of the valve spindle release device. Fig. 4: is a plan of same. Fig. 5 is a front view and side sectional elevation of valve rod showing the locking recess.

On the piston rod a is mounted a crosshead b to which is connected an oscillating lever c pivoted on a bracket ci carried by the pump valve boX e. The lever c carries a collar f which embraces the rod g which is connected to the ordinary valve spindle 7L. Upon the rod g above and below the collar f are arranged washers z', spiral springs y' and adjusting nuts 7e. The valve spindle l1, is provided at its lower end with an enlarged portion Z which is supported slidingly in a guide bracket m. This part Z has a recess a preferably formed in a hardened detachable plate 0.

Upon the bracket m are slidingly mounted Specicaton of Letters Patent.

Application led April 3, 1908.

Serial No. 424,907.

two spring pressed bolts p, the inner ends of which are adapted to engage with the recess a when either one or other bolt is opposite the said recess. A trip lever g is pivotally mounted on the bracket and has pins r adapted to co-act with a projecting portion on the bolts p. The lever g is operated by levers, link gear and adjustab e draw-bar s from the crosshead The operation of the gear is as follows It is assumed that the Valve is locked by the upper bolt p as shown in Fig. l in position for one of the ports to be full open to take steam, the main piston begins its stroke and the crosshead Z1 moving the operating lever c compresses the lower spring on the rod g of the valve spindle 71. as the piston nears the end of its stroke and reaches the desired point of cut-olf, the crosshead engages One of the nuts on the draw bar s of the tripping gear which n turn withdraws the bolt o from the recess a and allows the compressed spring j to move the valve t0 the opposite end of its stroke where it is again automatically held in position by the lower bolt until the corresponding point of cut-o on the return stroke. Thus the main engine will continue to operate its rown valve in a direct manner so long as motive fluid is supplied so as to move its own main piston.

The point of cut-off and the spring pressure necessary for moving the valve can be varied by adjusting the regulating nuts on the draw bar s and rod g respectively.

It is obvious I may substitute for the spiral springs any equivalent means for storing and giving out the energy from the main piston rod.

It will be recognized that the construction is very simple and the operation of the mechanism is such as to preclude any risk of damage to the engine when working under abnormal conditions.

Having now described my invention, what I desire to claim and secure by Letters Patent is A valve gear. for direct acting pumping engines, comprising an oscillating lever adapted to be oscillated by the main piston rod, a valve operating rod having a recess n therein, adjustable springs located one above and one below the oscillating lever and Patented Apr. 5, 1910.

adapted to be compressed by said lever,

spring pressed rods, one of which normally In testimony whereof I have signed my engages with the recess 1n the valve rod, e name to thls specleatlon 1n the presence of l0 lever adapted to Wltlldrznv one or the other two snbscrlblng Wltnesses.

of the spring controlled rods from the recess 4 T l l 4 1n the valve rod, av serles oi llnks connected HEB RY TGBLDS' to sald lever, and ad]ustable releaslng means Vltnesses:

operated by 2L man1 plston rod and con- JOHN HENRY SELLERS,

nected to said links. CHARLES CATTS. 

